Lubricating oil containing a viscosity index and extreme pressure additive comprising a sulphur and halogen containing olefin polymer



United States Patent Olfice 3,410,800 Patented Nov. 12, 1968 3,410,800LUBRICATING OIL CONTAINING A VISCOSITY INDEX AND EXTREME PRESSUREADDITIVE COMPRISING A SULPHUR AND HALOGEN CONTAINING OLEFIN POLYMER JohnFrederick Ford and Eric Simon Forbes, Sunbury-on- Thames, England,assignors to The British Petroleum Company Limited, London, England, acorporation of England No Drawing. Original application June 3, 1964,Ser. No. 372,365, now Patent No. 3,346,549, dated Oct. 10, 1967. Dividedand this application Apr. 3, 1967, Ser. No. 643,767 Claims priority,application Great Britain, June 14, 1963, 23,782/63 2 Claims. (Cl.252-48.8)

ABSTRACT OF THE DISCLOSURE Lubricating compositions having improved loadcarrying and viscosity properties are provided, which compositionsconsist essentially of a lubricating base oil having incorporatedtherein an oil soluble sulphurand halogen-containing olefin polymerprepared by polymerising, sulphurising and halogenating, in a singlestage, an alpha-olefin in the presence of a Friedel-Crafts catalyst.

This application is a division of our copending application Ser. No.372,365, filed on June 3, 1964, now Patent No. 3,346,549.

This invention relates to the preparation of sulphurandhalogen-containing olefin polymers suitable for use as additives forimproving the viscosity index and load carrying properties oflubricating oils, and to lubricating compositions containing suchpolymers.

According to the invention, an oil-soluble, sulphurandhalogen-containing olefin polymer is prepared by reacting an alphaolefin having up to 20 carbon atoms, preferably a methyl-substitutedbutene, pentene or hexene, e.g. 4-methylpentene-1, with a sulphur halideor oxyhalide, preferably chloride or bromide, in the presence of aFriedel-Crafts catalystand at a temperature within the range 50 to l20C., preferably 5 to 60 C., the molar ratio of olefin to sulphur halideor oxyhalide being 100:0.1-25, especially 100:2-15, and the molar amountof catalyst being greater than the molar amount of sulphur halide oroxyhalide.

Suitable Friedel-Crafts catalysts include aluminium chloride (S Clsulphur dichloride (SCl thionyl chloride, stannic chloride, borontrifluoride, titanium tetrachloride, hydrogen fluoride and mixturesthereof. Aluminium chloride is preferred.

Suitable sulphur halides and oxyhalides include sulphur chloride (S Clsulphur dichloride (SCI thionyl chloride (SOCl sulphuryl chloride (SO Clthe corresponding bromides and fluorides and mixtures thereof.

The reaction is preferably carried out in an inert solvent such as achlorinated hydrocarbon, e.g. methylene chloride, ethyl chloride, ethylbromide or carbon tetrachloride.

The invention also includes sulphurand halogen-containing olefinpolymers prepared by the method described above.

The invention further includes lubricating compositions consistingessentially of a major proportion of a lubricating base oil (which maybe mineral or synthetic) and a minor proportion, e.g. 0.1 to 25%,especially l-%, by weight of the composition, of a sulphurandhalogencontaining olefin polymer as specified above.

A number of actual preparations of polymers according to the inventionwill now be described by way of example.

Polymer A This polymer was'formed by reacting sulphur chloride andaluminium chloride with 4-methylpentene-1 at low temperatures, e.g. -55C., and using ethyl bromide as a solvent. Experimental details were asfollows:

S Cl was purified by distilling it over 2% sulphur and 1% animalcharcoal, the fraction boiling in the range 3031 C. under water pumpvacuum being used for the experiment. The ethyl bromide and4-methylpentene-1 were dried over a molecular sieve and pure, dry AlClwas used.

6.68 g. (0.05 M) A1Cl was added to a 500 ml. 3- necked flask togetherwith 200 ml. dried EtBr in a dry atmosphere in a glove-box; the mixturewas shaken until all the AlCl had dissolved. 3.38 g. (0.025 M)redistilled S Cl was added to the flask. 42.6, g. (0.5 M)4-methylpentene-l was placed in a sealed dropping funnel. The 500 ml.flask was attached with this dropping funnel, a nitrogen bleed, astirrer, a water condenser and a thermometer and placed in a bath ofacetone/solid carbon dioxide at -60 C.

Dry nitrogen was passed through the flask and the 4-methylpentene-1added slowly to the mixture over a period of 40 minutes, keeping theflask temperature between 50 and 55 C.

There were no obvious signs of polymerisation at this stage although thecolour of the solution had changed to a light green. After passing drynitrogen through for a further one hour to complete the reaction, ml.n-heptane was added as a higher boiling hydrocarbon solvent followed by100 ml. distilled water to render the AlCl catalyst unreactive. Onaddition of the water, the temperature of the mixture increased rapidlyto -10 C. and a thick layer of white polymer was evident on top of ayellow-coloured solution.

The polymer solution was heated up to the boiling point of the ethylbromide and this solvent was stripped olt. The yellow solution waswashed four to five times with equal portions of distilled water toremove unreacted material and any acids formed during the reaction. Thesolution plus water was finally stirred at 80 C. for 1 hour and thewater separated off. The polymer solution was dried over anhydrousmagnesium sulphate and filtered to give a clear deep yellow solution.The n-heptane was stripped off by heating up to C. first using a waterpump vacuum and finally using an oil pump to a pressure of 1 mm. Hg. 37g. of a dark-brown sticky polymer (Polymer A) was obtained whichcontained 2.8% sulphur and 3.3% chlorine.

The viscosity index-improving and load carrying (EP) properties of thepolymer were tested in two refined lubricating oils (P and Q) obtainedfrom Middle East crude oils. The results are given in the table below.

Polymer B 13.34 g. (0.10 M) AlCl together with 5.19 g. (0.05 M) sulphurdichloride (SO1 was added to 150 ml. dried ethyl bromide in a 500ml.three-necked flask placed inside a dry glove box. As with sulphurmonochloride, a red coloured solution was formed. 42.6 g. (0.5 M)4-methylpentene-l was added over 30 minutes under N keeping the reactiontemperature at -55:2 C. 'by means of an acetone-cardice (solid carbondioxide) bath. The polymer was worked up in a similar manner to thesulphur monochloride polymer and 30 g. of a dark brown polymer wereobtained. It had a sulphur content of 1.48% wt. and a chlorine contentof 2.05% wt. Test data on this polymer are given in the table.

Polymer C 10.02 g. (0.075 M) AlCl together with 6.76 g. (0.05 M)sulphuryl chloride (SO CI were added to 150 ml.

3 dried ethyl bromide in a 500 ml. three-necked flask and once again ared solution was obtained. 42.6 g. of (0.5 M) 4-methylpentene-1 wereadded slowly to this solution under N at -55i2 C. and after working up,23 g. of

4 C and D) were also tested for copper corrosion by the ASTM CopperCorrosion test and, as will be seen from the table, they passed thistest. The lubricants containing Polymers C and D also passed thehydrolytic stability a dark brown low molecular weight polymer wasobtained 5 test.

having a sulphur content of 1.51% wt. and a chlorine If desired, thepolymers according to the invention can content of 3.70% wt. Test dataon this polymer are given be treated to remove any acidity that may bepresent,

in the table, e.g. by percolation through an alumina column, stirringPolymer D with alumina or alkali washing.

20.04 g. (0.15 M) AlCl and 11.92 g. 0.10 M) thionyl f g f n f chloridesocl were added to 300 m1. ethyl bromide to mg 9 5 P mg Y 0 form ayellow solution 852 (1 M) 4 methy1pentene 1 a lubr1cat1ng base 011containing dissolved therein 0.1 was added over minutes keeping thereaction temby 8 of the composltlom of a Sulphur- 9 Peta/cure at Q andafter Working up in a simihalogen-containmg olefin polymer prepared byreacting lar manner to previous examples except that more rigor- 15 afeed olefin Sel f th@ g p COIlSiStlng of methyl" ous washing of thepolymer took place, g. of a light subst1tuted alpha-butene,methyl-substituted alpha-penbrown polymer were obtained having a sulphurcontent tene, and methyl-substituted alpha-hexene with a sulphur of0.68% wt. and a chlorine content of 1.05% wt. Test compound selectedfrom the group consisting of sulphur data on this polymer are given inthe table below. chlorides, sulphur oxychlorides, sulphur bromides andTABLE Kinematic Viscosity Shell Four Ball Test Hydrolytic Stability Test(centlstokes) Results Copper 0 VI Corro- Oil Layer Water Layer 100F.140F. 210 F. MHL, 2 SDL, ISL, WL, siou (38 C.) (00 C.) (09 0.) kg. kg.kg. kg. Test TAN SAN TAN SAN Base oilP 45.04 18.84 6.53 103 BaseoilPplus2% wt.PolymerA. 59.67 24.23 8.19 114 BaseoilPplus4%wt.PolymerA77.94 31.02 10.25 119 Base 011 242.4 18.25 00 Base oil Q, plus 5% wt.Polymer- A. 428v 3 29. 62 103 Base oil Q, plus 5% wt. Polymer B. 27. 06101 Base oil Q plus 5% wt. Polymer 0.. 22. 05 .4 0. 0.10 0. Base oil Qplus 5% wt. Polymer D 28. 20 107 39.5 100 220 0.08 0.08 Nil 0.02 NilNotes on the table (1) The Copper Corrosion Test used was the ASTM Dtest.

(2) The Hydrolytic Stability Test consisted of stirring a polishedcopper rod at 1000 rpm. in a mixture of 100 g. of the oil blend plus 200g. water at 90 C. for five hours. The total acid and strong acid numbersof the oil and water layers are measured after the test.

(3) Abbreviations:

MHL Mean hertz load.

2 /2 SIL 2 /2 second delay load.

ISL Initial seizure load.

WL Welding load.

TAN Total acid number (mg. KOH/g.). SAN Strong acid number (mg. KOH/g.).VI Viscosity index.

The results in the table show that all the polymers according to theinvention acted as viscosity index improvers and as EP additives. Thelubricants containing the polymers made with sulphur oxyhalides(Polymers References Cited UNITED STATES PATENTS 2,291,404 7/1942 MorWay25248.8 XR 2,786,031 3/1957 Givens 252-488 2,827,434 3/1958 Wierber25248.8 XR 3,081,294 3/1963 Beynon et a1. 25248.8 XR

DANIEL E. WYMAN, Primary Examiner.

W. H. CANNON, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,410,800 November 12, 1968 John Frederick Ford et al.

It is certified that error appears in the above identified patent andthat said Letters Patent are hereby corrected as shown below:

Column 1, lines 49 and 50, (S Cl sulphur dichloride; (SCl thionylchloride"'shou'ld'read zinc chloride, antimony chloride, ferric chlorideColumn 3, line 6, "1.51% wt." should read 1.15% wt.

Signed and sealed this 3rd day of March 1970.

(SEAL) Attest:

WILLIAM E. SCHUYLER, JR.

Commissioner of Patents Edward M. Fletcher, J r.

Attesting Officer

